Sir Alex Ferguson has spent the last few weeks working out how to stop Francesco Totti and, if Manchester United are going to reach the Champions League semi-finals, it is clear they are going to have do it the hard way. Ferguson's squad was notable for the number of absentees when they arrived in Rome yesterday, with Rio Ferdinand the only fit member of the team's first-choice defensive quartet.

With Nemanja Vidic recovering from a broken collar bone, the task of shackling Totti will fall to Wes Brown, a player Ferguson regards as "the best natural defender in the country" but who is very much third-choice centre-half at Old Trafford. Brown will partner Ferdinand in a reconfigured back line that will have John O'Shea filling in for the injured Gary Neville at right-back and Gabriel Heinze replacing Patrice Evra on the left.

"The options are obviously limited and what has happened with the back four is a concern," Ferguson admitted. "We have pencilled in Vidic to return in the middle of May but until then we just have to deal with it and, for Wes, this is a great break for him. He started off the season in the team because Vidic was injured from the World Cup. He has played with Rio many times and I have no concerns about him at all.

"Yes, Totti is a great player but we have played a lot of clubs with great players in the past," Ferguson said. "Roma have a system which is difficult to play against. They don't have a central striker; instead they play with two wide players and flood the midfield."

Ferguson was dealt another blow when Park Ji-sung was ruled out after injuring his knee in Saturday's 4-1 victory over Blackburn Rovers. Louis Saha and Darren Fletcher have rejoined the squad after injury, though neither is likely to start in the Stadio Olimpico, and Ferguson has so few options he was forced to name Craig Cathcart, an 18-year-old defender, among the travelling party.

Roma, along with Milan, have the meanest defence of the clubs still in the competition, having conceded only four goals in Europe this season, and Ferguson believes the tie will be heavily influenced by how the Italians cope with Wayne Rooney and Cristiano Ronaldo.

"When we played Milan in the quarter- final a couple of years ago Wayne and Cristiano lacked the experience to handle it," he said. "It was a big game against experienced guys and it was hard for them. They were young boys at the time but they have matured and I think Cristiano is the best player in the world right now. And I'm pleased with Rooney's form too, I must say that. His positional play and his movement is fantastic and you have to look at the amount of work he gets through in every game. He scored 19 goals last season and, if he beats that total this year, he should be happy. He is on 15 at the moment and that is his target."

Ferguson may consider Totti to be "a great player" but the Italian is unlikely to feature on his list of transfer targets after he ruled out a move to England yesterday. "I don't like England," said the 30-year-old, who was born in Rome and has spent his entire career there. "I don't like English football or weather."